|Publication number||US4740859 A|
|Application number||US 06/865,143|
|Publication date||Apr 26, 1988|
|Filing date||May 20, 1986|
|Priority date||Mar 31, 1983|
|Publication number||06865143, 865143, US 4740859 A, US 4740859A, US-A-4740859, US4740859 A, US4740859A|
|Inventors||Hercel A. Little|
|Original Assignee||Leon A. Hoskamer|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (10), Referenced by (37), Classifications (8), Legal Events (7)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This is a continuation of application Ser. No. 480,751 filed on Mar. 31, 1983, which is a continuation of application Ser. No. 323,110 filed on Nov. 19, 1981, which is a continuation of application Ser. No. 094,981 filed on Nov. 16, 1979.
1. Field of the Invention
This invention has relation to the use of surge suppressors in the form of varistors to prevent random and switching transients in incoming power transmission lines from reaching electrical equipment connected to those lines, and the use of normally activated neon glow tubes or other voltage drop indicators to constantly simultaneously indicate that these surge suppressor circuits are in operative condition and to indicate that there is no short circuit in such transmission lines.
2. Description of the Prior Art
In alternating current power systems, it is known to connect a varistor between an incoming power line and the ground, and it is known to provide a fuse in series with this varistor. Further, it is known to connect a pilot light between a power line and neutral or ground to indicate the presence or absence of electrical energy in that line. Before the present invention, however, there was no way to indicate in a single unit both that the surge suppressor was in condition to operate properly to protect against overload surges and that there was no short circuit in the power lines.
One obvious advantage of using a surge suppressor and nonshort circuit monitor unit is to protect the electrical equipment connected to the incoming transmission lines from surges which can be damaging to that equipment. A less obvious but very important advantage is to prevent such surges from adversely affecting the readings on the electric watt meter. Transient overload surges add nothing to the performance of line electrical equipment on the surging lines, but do cause the watt meter to register a higher wattage than is actually used by the equipment.
Most electrical fires start because of short circuits. A major advantage of a combined nonshort circuit monitor and surge suppressor unit is that it gives an instantaneous indication of a condition where the absence of a short circuit can no longer be assumed. This allows instant remedial action to be taken.
A further advantage is that the visual indicator indicates simultaneously both the fact that the surge suppressor function is in place and operative and the fact that the incoming power lines are not shorted to ground or neutral.
In the parent application, the following were cited by the Examiner as prior art.
U.S. Pat. No. 4,191,985 to Phillips, Jr. in March 1980;
U.S. Pat. No. 3,693,053 to Anderson in September 1972;
U.S. Pat. No. 4,023,071 to Russell in May 1977;
U.S. Pat. No. 4,089,032 to Orfano in May 1978; and
U.S. Pat. No. 3,894,274 to Rosenberry, Jr. in July 1975.
A transient voltage surge suppressor and line short monitor unit for use with an alternating current power transmission system including a ground or other neutral path and a plurality of incoming alternating current power lines connected to at least one electrical appliance being powered by that system includes a case or casing in which is located a current limiting device such as a varistor for each such incoming power line, and a circuit protective device such as fuse or circuit breaker for each such voltage limiting device. Leads from each power line and the neutral line extend to position inside the case. In the form of the invention shown, each such varistor and fuse are connected in series with each other and connected between a lead from one of the incoming power lines and a ground or neutral lead line. A voltage drop indicator such as a neon lamp is also positioned in the casing and is connected in parallel with each of the varistors. The lamp can be observed from outside the case or casing.
In operation, when a transient voltage surge of over a predetermined maximum voltage occurs between any one of the incoming alternating current power transmission lines and a neutral path such as ground, the voltage limiting device will go into conduction to limit to a predetermined maximum, the voltage between that tranmission line and the neutral path. At all other times, the voltage drop across the voltage limiting device (varistor in the form of the invention as shown) will be equal to the nominal alternting current voltage of the incoming line with respect to the neutral path, and the voltage drop indicator (neon lamp in the form of the invention as shown) will give an observable indication that such portion of the transient voltage surge suppressor is in operative condition and ready to limit any voltage surge as it may occur.
Should one or more of the incoming power lines become short circuited to ground or another neutral path anywhere along the power transmission system outside of the unit of the present invention, the voltage drop across the voltage drop indicator will disappear, and the voltage drop indicator (neon lamp in the form of the invention as shown) will cease giving its observable indication.
Should there by any discontinuity in any leg of the transient voltage surge suppressor/line short monitor unit, including opening of the circuit protective device (fuse in the form of the invention as shown), there will be no voltage drop across the voltage limiting device (varistor), and the voltage drop indicator (neon lamp) will not be operative.
Whether the voltage drop indicator becomes inoperative because the circuit protective device has been blown out, or because the power line protected by that device has been shorted to ground or other neutral path, this inoperativeness of the voltage limiting device gives an instant notification that at least one of the conditions for proper operation of the alternating current transmission system including the surge suppressor is no longer present. Remedial action can then be promptly undertaken.
FIG. 1 is a partial schematic representation of a three-phase alternating current power transmission system feeding electrical equipment and a plan view of a surge suppressor/line short monitor unit of the present invention associated with that system; and
FIG. 2 is a schematic representation of the circuit diagram of the surge suppressor/line short monitor unit of FIG. 1.
A transient voltage surge suppressor and line short monitor unit of the present invention is shown in FIG. 1 to be associated with an incoming three-phase alternating current power transmission system including incoming power lines 12, 13 and 14 connected through an electric watt meter 16 to buss bars 18, 19 and 20, respectively, inside of a distribution panel 22. Connected to these buss bars by internal power lines 24, 25 and 26 is an electrical appliance load 28 typified in FIG. 1 as a three-phase electric motor.
The suppressor/monitor unit 10 has leads 30, 31 and 32 each connected with one of the buss bars 18, 19 and 20, respectively, and to circuit protective devices such as fuses, 34, 35 and 36 inside of the casing of the unit. In a 120/208 volt three-phase system where the suppression level is to be limited to 500/1000 volts peak, fuses rated at 28 amperes at 125 volts have been found to be satisfactory.
Each of these fuses is in turn connected to one of three voltage limiting devices such as varistors 38, 39 and 40, and the other end of each of these varistors is connected to a neutral line 42. A ground connection is indicated at 44. Varistors which limit the voltage between the buss bars 18, 19 and 20 and neutral to 500 volts have been found to be satisfactory.
Voltage drop indicators such as neon lamps 46, 47 and 48 are each connected in series with one of three circuit limiting devices such as resistors 50, 51 and 52, respectively, and each lamp/resistor pair is connected across one of the varistors to neutral line 42. Resistors having a resistance of approximately 30K ohms have been round to be satisfactory.
In operation, when a transient voltage surge of over 500 volts occurs between one or more of the buss bars 18, 19 and 20 and neutral line 42, the varistor associated with such buss bar will conduct to limit the voltage between the buss bar and the neutral line to a maximum of 500 volts, thus limiting the amount of erroneous watt meter reading which can be generated, and also at the same time limiting the peak surge voltage to the electrical motor 28 between any two internal power lines to 1000 volts.
The presence of this surge in the power line and consequently the momentary conduction of the varistor to limit the maximum voltage may be indicated by a momentary flicker of the associated neon lamp.
At any time when the incoming current transmission system is energized, and one of the incoming power lines 12, 13 or 14, the buss bars 18, 19 or 20, or the internal power lines 24, 25 or 26 becomes shorted to neutral or ground, there will no longer be a voltage drop across the fuse/varistor pair associated with that leg of the transmission line. Accordingly, there will be no voltage drop across the varistor and across the lamp/resistor pair connected across the varistor. Thus the neon lamp or bulb will not be energized and will go out and will remain out for so long as such a short circuit is present.
At all times when no surge is present on the power line due to the presence of a voltage over the predetermined maximum of 500 volts, for example, and when no such short circuit is present, the three neon lamps 46, 47 and 48 will be lighted and will indicate that the surge suppressor is effectively standing by to handle any transient voltage surges which may occur, and to indicate that there is no short circuit of any of the three power line legs of the system.
A visual inspection can be maintained of the suppressor/monitor unit 10, and as long as these neon lamps are lighted, the inspector is assured that any spurious meter readings due to transients are being limited and that no transient electromotive force exceeding 500 volts from line to neutral is being transmitted to the appliance protected by the surge suppressor. The inspector is also assured that there is no short circuit present in the power lines themselves.
When any one or more of these neon lamps go out, immediate remedial action can be taken, first to determine whether there is a short circuit of one of the lines to ground or other netural path, and then to see if one of the fuses 34, 35 or 36 has been blown.
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3456572 *||Dec 18, 1967||Jul 22, 1969||Ford Motor Co||Vehicle panel assembly|
|US3693053 *||Oct 29, 1971||Sep 19, 1972||Gen Electric||Metal oxide varistor polyphase transient voltage suppression|
|US3840781 *||Jul 2, 1973||Oct 8, 1974||Brown D||Small plug-type surge protector|
|US3894274 *||Jul 1, 1974||Jul 8, 1975||Gen Electric||Electric motor transient voltage suppressing circuit|
|US4023071 *||Jun 9, 1975||May 10, 1977||Fussell Gerald W||Transient and surge protection apparatus|
|US4068279 *||Oct 28, 1976||Jan 10, 1978||Byrnes Gerald J||Power monitor|
|US4089032 *||Sep 8, 1976||May 9, 1978||William Dell Orfano||Plug-type transient surge suppressor|
|US4152743 *||Jun 27, 1977||May 1, 1979||Comstock Wilford K||Transient voltage suppression system|
|US4168514 *||Dec 16, 1977||Sep 18, 1979||General Electric Company||Combination circuit breaker-lightning arrestor|
|US4191985 *||Sep 16, 1977||Mar 4, 1980||Phillips Charles M Jr||Interrupter|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4868412 *||Oct 28, 1988||Sep 19, 1989||Sundstrand Corporation||Distributed control system|
|US4922366 *||May 12, 1988||May 1, 1990||Transnational Energy Systems, Inc., Dba Tesco||Meltable conductor to be used in series with voltage suppressors|
|US4975798 *||Sep 5, 1989||Dec 4, 1990||Motorola Inc.||Voltage-clamped integrated circuit|
|US5010438 *||Jun 16, 1989||Apr 23, 1991||Square D Company||Plug-in transient voltage suppressor module|
|US5148345 *||Mar 5, 1990||Sep 15, 1992||Allina Edward F||Prepackaged electrical transient surge protection|
|US5153806 *||Jun 7, 1989||Oct 6, 1992||Corey Lawrence G||Transient surge suppressor and alarm signal circuit|
|US5412526 *||Feb 10, 1993||May 2, 1995||Square D Company||Surge arrester circuit and housing therefor|
|US5543999 *||Nov 14, 1994||Aug 6, 1996||Riley; Andrew T.||Surge protector for computer equipment|
|US5583734 *||Nov 10, 1994||Dec 10, 1996||Raychem Corporation||Surge arrester with overvoltage sensitive grounding switch|
|US5627720 *||Aug 11, 1995||May 6, 1997||Lewis; Keith A.||Power distribution box with surge suppressor|
|US5652820 *||Nov 13, 1995||Jul 29, 1997||Act Communications, Inc.||Fiber optic splice closure and protection apparatus|
|US5654857 *||Jul 19, 1995||Aug 5, 1997||Leviton Manufacturing Co., Inc.||Ground fault circuit interrupt system including auxiliary surge suppression ability|
|US5724221 *||Feb 2, 1996||Mar 3, 1998||Efi Electronics Corporation||Direct contact varistor assembly|
|US5748093 *||Mar 19, 1996||May 5, 1998||Joslyn Electronic Systems Corporation||Electrical surge protection system with condition monitoring|
|US5790359 *||Oct 17, 1997||Aug 4, 1998||Joslyn Electronic Systems Corporation||Electrical surge protector with thermal disconnect|
|US5841615 *||Apr 16, 1997||Nov 24, 1998||Leviton Manufacturing Co., Inc.||Ground fault circuit interrupt system including auxiliary surge suppression ability|
|US5914845 *||May 1, 1998||Jun 22, 1999||Chase; Ronald Cole||Surge protector system|
|US5986870 *||Sep 16, 1997||Nov 16, 1999||Joselyn Electronics Systems Company||Electrical surge protector with protective enclosure|
|US6453106||Jun 30, 2000||Sep 17, 2002||Ge-Act Communications, Inc.||Method and apparatus for a cable location and protection system|
|US6519125 *||May 24, 2001||Feb 11, 2003||Relcom, Inc.||Current limiter for a network|
|US6870722||Nov 14, 2002||Mar 22, 2005||Relcom, Inc.||Enhanced spur cable circuit protection device and method for its implementation|
|US7023680||Oct 29, 2003||Apr 4, 2006||Psg Enterprises, Inc.||Transient voltage protection and ground status monitoring apparatus and method|
|US7561399 *||Jul 14, 2009||Landis+Gyr, Inc.||Excessive surge protection method and apparatus|
|US7729099 *||Nov 13, 2007||Jun 1, 2010||Siemens Aktiengesellschaft||Surge arrester|
|US20030131293 *||Nov 14, 2002||Jul 10, 2003||Michael Strauser||Enhanced spur cable circuit protection device and method for its implementation|
|US20060126255 *||Feb 9, 2006||Jun 15, 2006||Landisinc.||Excessive surge protection method and apparatus|
|US20060221532 *||Feb 27, 2006||Oct 5, 2006||Bellsouth Intellectual Property Corporation||Apparatus for protecting DC-powered equipment from power events occurring at the equipment power input|
|US20080068027 *||Sep 20, 2006||Mar 20, 2008||L-3 Communications Corporation||Power line surge arrestor monitoring system|
|US20080291596 *||Nov 13, 2007||Nov 27, 2008||Siemens Aktiengesellschaft||Surge Arrester|
|US20140022683 *||Feb 22, 2012||Jan 23, 2014||COSTRUZIONI ELETTROMECCANICHE P. TORRESAN S.r.l.||Device for protecting electric equipment from overvoltage and lightening|
|US20140139349 *||Oct 29, 2013||May 22, 2014||Baker Hughes Incorporated||Systems and Methods for Detecting and Communicating Failure of Integral Surge Suppression in Drive Systems for Downhole Equipment|
|CN100570979C||Nov 28, 2003||Dec 16, 2009||徐文远;崔 禹||Method and device for reducting energization transients in a three phase Y-connected load|
|CN102447250A *||Sep 30, 2010||May 9, 2012||深圳茂硕电源科技股份有限公司||Simple and practical lightning protection circuit|
|CN102904237A *||Oct 23, 2012||Jan 30, 2013||四川省电力公司内江电业局||Surge protecting box|
|CN102904238A *||Oct 24, 2012||Jan 30, 2013||深圳市雷博斯科技有限公司||Overheat, overcurrent and overvoltage lightning protector|
|WO1990016103A1 *||Jun 11, 1990||Dec 27, 1990||Square D Company||Plug-in transient voltage suppressor module|
|WO2007064960A2 *||Nov 30, 2006||Jun 7, 2007||University Of South Florida||Mov failure mode identification|
|U.S. Classification||361/56, 361/111|
|International Classification||H02H9/04, H02H3/04|
|Cooperative Classification||H02H3/048, H02H9/04|
|European Classification||H02H9/04, H02H3/04E|
|Jul 3, 1991||AS||Assignment|
Owner name: HOSKAMER, THOMAS, MINNESOTA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:HOSKAMER, LEON;REEL/FRAME:005755/0251
Effective date: 19910320
|Oct 28, 1991||FPAY||Fee payment|
Year of fee payment: 4
|Nov 26, 1991||REMI||Maintenance fee reminder mailed|
|Sep 18, 1995||FPAY||Fee payment|
Year of fee payment: 8
|Nov 16, 1999||REMI||Maintenance fee reminder mailed|
|Apr 23, 2000||LAPS||Lapse for failure to pay maintenance fees|
|Jul 4, 2000||FP||Expired due to failure to pay maintenance fee|
Effective date: 20000426